Claude - Block npm / npx

settings.json

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "./.claude/use-pnpm-hook.sh"
          }
        ]
      }
    ]
  }
}

use-pnpm-hook.sh

#!/bin/bash
# hook to block npm/npx commands and suggest pnpm

# Read JSON input
input=$(cat)
command=$(echo "$input" | jq -r '.tool_input.command // ""')

# Check for npm or npx command and block if found
if [[ "$command" =~ ^npm[[:space:]] || "$command" =~ ^npx[[:space:]] ]]; then
    echo '{"decision": "block", "reason": "npm/npx commands are not allowed. Please use pnpm instead."}'
    exit 2
fi

# Allow the command
exit 0

We need more CC hooks from CJ!!!